Ash removal system for incinerators

ABSTRACT

The improvement, in an incinerator, of conveyor means for automatically removing the burnt material or ash from the ash pit of the incinerator and for transporting it to a remote location. A control is provided for automatically operating the conveyor and a temperature sensing device is provided in the ash pit for stopping the conveyor when the accumulation of ash is reduced to a minimum predetermined amount. It is preferable that the conveyor operating cycle be initiated when the incinerator charging door is opened to permit the feeding of the material to be burned from an automatic feed means.

[ 1 Oct. 15,1974

United States Patent [191 Dewey et al.

3,667,627 6/1972 Martin ct 3,728,977 4/1973 Brannan.............3,749,031 7/1973 Burden, Jr.

[ ASH REMOVAL SYSTEM FOR INCINERATORS Primary ExaminerKenneth W. SpragueAttorney, Agent, or Firm-Parrott, Bell, Seltzer, Park & Gibson [75]Inventors: Ernest A. Dewey, Richmond, Va.;

Richard F. Clements, Charlotte, NC.

Environmental Control Products,

[73] Assignee:

Inc., Charlotte, NC.

July 12, 1973 [21] Appl. No.: 378,657

[57] ABSTRACT I The improvement, in an incinerator, of conveyor [22]Filed:

means for automatically removing the burnt material or ash from the ashpit of the incinerator and for transporting it to a remote location. Acontrol is provided for automatically operating the conveyor and atemperature sensing device is provided in the ash pit for stopping theconveyor when the accumulation of ash is reduced to a minimumpredetermined amount. It is preferable that the conveyor operating cyclebe initiated when the incinerator charging door is opened to permit thefeeding of the material to be burned from an automatic feed means.

12 Claims, 6 Drawing Figures RmwR fifix 1 HH 65 6 00ml 1 1 11 mumw .m ll ..1 1F "m. R N s T. ..u m m N m: 0 E m: 1 v T n ."O WA "u" in. W: "m Smm mmm r. m nu cT .m "N" nA n mmm mTa U" .RSRWM h e R 0 m. 57 UIF 377HUN M mun 555i U 2 2 3 ASH REMOVAL SYSTEM FOR INCINERATORS The presentinvention relates generally to an ash removal system for incineratorsand more particularly to such a system which is automatically controlledin response to the feeding of waste material into the incinerator.

Heretofore, various types of systems have been proposed for the removalof the burnt material or ash from the ash pit of an incinerator.However, these prior systems have either operated on a continuous basisor on an automatic time cycle. In either case, it is difficult toproperly adjust the ash removal system to the proper burning cycle sothat the ash is removed at the proper rate. If too great an amount ofash is permitted to accumulate, it will adversely effect the burning ofthe waste material. If too small an amount of ash is in the ash pit, theheat from the combustion chamber can adversely effect the ash removalmechanism.

Accordingly, it is an object of this invention to provide an ash removalsystem which overcomes the difficulties and problems presented in priorash removal systems and which is characterized by being operable inresponse to the feeding of waste material to be burned and maintains theproper amount of ash in the ash pit.

This object is accomplished in the present invention by providing aconveyor communicating with the ash pit and being operable to remove theash from the ash pit and transport it to a remote location. A control isprovided for automatically initiating the operating cycle of theconveyor in response to the feeding of waste material to be burned intothe combustion chamber. A temperature sensing device is provided in theash pit for interrupting the operating cycle and stopping the conveyorwhen the accumulation of ash is reduced to a minimum predeterminedamount. The operating cycle of the ash removal system is preferablyinitiated when the incinerator charging door is opened to receive thewaste material from the automatic feed means for the incinerator.

Other objects and advantages of the invention will appear as thedescription proceeds, when taken in connection with the accompanyingdrawings, in which-- FIG. 1 is an isometric view of an incinerator ofthe type having a main and secondary combustion chamber and illustratingthe present ash removal system applied thereto;

FIG. 2 is an enlarged fragmentary vertical sectional view takensubstantially along the line 22 in FIG. 1;

FIG. 3 is a longitudinal vertical sectional view taken substantiallyalong the line 33 in FIG. 1 and illustrating the manner in which theendless drag chain passes through the ash pit of the incinerator;

FIG. 4 is a sectional plan view taken substantially along the line 44 inFIG. 3;

FIG. 5 is a vertical sectional view taken substantially along the line5-5 in FIG. 3; and

FIG. 6 is a somewhat schematic and diagramatic view of the incinerator,illustrating a portion of the ash removal system and illustrating thecontrols for the operation of the ash removal system.

The ash removal system of the present invention is illustrated anddescribed in operation with a controlled emission incinerator apparatusof the type disclosed in US. Pat. No. 3,543,700, issued Dec. 1, 1970,and assigned to the present assignee. This incinerator is illustrated asbeing provided with an access or charging door of the type disclosed inUS. Pat. No. 3,669,040, issued June 13, 1972, and assigned to thepresent assignee. The automatic feed means, illustrated in dotted linesin FIG. 6, may be of the general type disclosed in US. Pat. No.3,708,078, issued Jan. 2, 1973, and assigned to the present assignee.However, it is to be understood that the ash removal system of thepresent invention may be used in connection with other types ofincinerators which may be provided with different types of devices formanually or automatically feeding the waste material into theincinerator to be burned.

Referring particularly to FIG. 1, the controlled emission incineratorincludes a main combustion chamber, broadly indicated at 10, whichcommunicates with a secondary combustion chamber 11, and exhaust stackmeans 12 having the lower end thereof communicating with the interior ofthe secondary combustion chamber 11. As best shown in FIG. 3, an ash pit13 is provided in the forward end of the main'combustion chamber 10 andis preferably lined with refractory material of the type which isnormally used in an incinerator.

The ash removal system of the present invention comprises means forautomatically removing the burnt ash from the ash pit 13 and conveyingit to a remote location where it may be deposited in suitable containersor a truck or the like. The conveyor means comprises an endless dragchain 14 which removes the ash from the ash pit 13 and deposits it uponthe horizontal portion of an elevator conveyor, broadly indicated at 15(FIG. 2). Drive means, in the form of an electric motor 16 (FIG. 2) isprovided for imparting movement to the drag chain 14 and in a manner tobe presently described.

Opposite end portions of the drag chain 14 are suitably supported onsprockets 17, 18 (FIG. 3) and the sprocket 17 is preferably supportedfor adjustment to maintain the drag chain 14 under the proper tension.The upper reach of the drag chain 14 extends through the bottom of theash pit 13 and enters the ash pit through an entry opening 20 and leavesthe ash pit through an exit opening 21 having a doctor gate 22 supportedfor vertical movement in the exit opening 21 and above the drag chain14. Means, to be presently described, is provided for adjusting thevertical position of the doctor gate 22 to thereby aid in determiningthe amount of ash which is removed from the ash pit 13 by the drag chain14. The drag chain 14 is surrounded by support framing and a housing 24which is provided with access doors 25 at suitable locations to permitinspection and access to the drag chain 14.

The doctor gate 22 (FIGS. 3 and 5) is vertically adjustable by a meansof a hand wheel 27 which is fixed on one end of a control shaft 28. Thecontrol shaft 28 is supported for rotation in the housing 24 and haspinions 29, 30 fixed thereto which engage respective racks 31, 32supported on the gate 22. Thus, by rotating the wheel 27, the gate 22may be raised or lowered above the upper surface of the upper reach ofthe drag chain 14 to thereby vary the size of the exit opening 21 andpermit a greater or lesser amount of ash to be removed from the ash pit13.

The ashes removed by the drag chain 14 are carried along to an opening35 (FIG. 3) beneath a wire brush 36 where they fall by gravity onto thehorizontal flight of the elevator conveyor 15. A rectangular housing 40surrounds the elevator conveyor and extends upwardly from the housing 24surrounding the drag chain 14. The ashes transferred from the drag chain14 and onto the conveyor 15 are raised upwardly and discharged at theupper end, as illustrated in FIG. 1, into any suitable container orremoval truck or the like. As shown in FIG. 1, drive means in the formof an electric motor 41 is provided for imparting driving movement tothe elevator conveyor 15.

As best illustrated in FIGS. 2 and 3, the drive motor 16 impartsmovement to the drag chain 14 by means of a reduction drive unit 43, adrive sprocket 44, a chain 45, and ,a sprocket 46 which is fixed on adrive shaft 47. The drive shaft 47 is supported for rotation in thehousing 24 and the sprocket 18 is fixedly supported on the drive shaft47.

In accordance with the present invention, temperature sensing means ispositioned in the ash pit 13 and is operable to stop the conveyor meanswhen the amount of ash accumulated in the ash pit is reduced to aminimum predetermined amount. In the present instance, the temperaturesensing means is in the form of a thermocouple type sensor 50 (FIG. 6)which extends into the ash pit 13 and is connected by wires 51, 52 to anadjustable control switch 53. The control switch 53 is adjusted so thatthe drive means for the conveyor means is interrupted when theaccumulation of ash in the ash pit is reduced to a minimum level. It isto be understood that the thermocouple sensor 50 and the controlswitch53 operate in response to the temperature in the ash pit, which isdetermined by the amount of ash present therein. Thus, the temperatureat the location of the thermocouple 50 is reduced when the ash pit issubstantially full of ashes and is increased as the accumulation of ashin the ash pit is reduced. This insures that a sufficient protectivelayer of ashes is always present to prevent damage to the drag chain 14from the heat in the combustion chamber 10.

The control switch 53 is connected at one side to a main line 54 bymeans of a wire 55 and is connected at its other side to a main line 56by a wire 57. The control switch 53 is also connected to a solenoidswitch 58 by a wire 59. A wire 60 connects the other side of thesolenoid switch 58to the main line 56. The main line 56 is connected toone side of an ash removal drive motor starter 62 and the other side isconnected to the main line 54. A solenoid switch 63 is interposed in themain line 54 and is connected by a wire 64 to the main line 56. A wire65 extends from the other side of the solenoid switch 63 and to one sideof the solenoid switch 58. A wire 66 is connected to the other side ofthe solenoid switch 58 and its other end is connected to one side of atimer controlled solenoid switch 67. A wire 68 connects the other sideof the switch 67 to the main line 54. A normally open charging dooroperated switch 69 is connected at one side to the wire 66 by a wire 70.A wire 71 is connected at one end to the other side of the switch 69 andits other end is connected to the main line 54. The switch 69 isnormally open and it closes when the incinerator access or charging door72 is opened.

METHOD OF OPERATION When the automatic feed means 73 operates and the 6door 72 opens, the switch 69 closes to close the switch 63 and completethe circuit to the drive motor starter 62 and start the operating cycleof the ash removal system. The timer switch 67 is actuated when switch63 is closed and the drag chain 14 will normally continue to operate forthe time set on the timer switch 67. However, if enough ash is removedto increase the temperature in the ash pit 13 a sufficient amount toclose control switch 53, the circuit will be completed to switch 58 andit will open, thereby opening switch 63 and breaking the circuit to theash removal drive motor starter 62 so that movement of the drag chain isinterrupted.

If desired, the ash removal drive motor starter 62 can also operate theelevator conveyor drive motor 41. However, it is preferred that theelevator conveyor 15 operate continuously while the incinerator is inoperation. Thus, the drive means for the conveyor means is actuated eachtime the charging door 72 is opened and the automatic feed means 73 isoperated. The ash removal system continues to operate, unlessinterrupted by the operation of switch 53, until the pre-set time cycleis completed.

If desired, the control circuit of the ash removal system of the presentinvention may be changed so that the drag chain 14 is automaticallyoperated to remove the ash from the ash pit in response to thetemperature in the ash pit 13. In this case, the switch 53 would controlthe main line switch 63 to the drive motor starter 62. Then, the ashremoval system would operate when a predetermined amount of ashaccumulates in the pit and would also operate to stop the ash removalsystem when the amount of ash in the ash pit is reduced a given amountbelow the predetermined amount.

The incinerator charging means is illustrated and described as includingthe charging door 72 and the single ram type automatic feed means 73.However, it is to be understood that the charging door 72 can beeliminated if an automatic feed means is used which includes doublerams, of the type described in said US. Pat. No. 3,708,078. In thiscase, the switch 69 would be closed by the operation of the automaticfeeder. Also, the incinerator may be manually charged and the opening ofthe charging door would still close the switch 69 and start the ashremoval cycle.

In the drawings and specification there has been set forth a preferredembodiment of the invention, and although specific terms are employedthey are used in a generic and descriptive sense only and not forpurposes of limitation.

That which is claimed is:

1. In an incinerator including a combustion chamber for burning wastematerial, means for charging the combustion chamber with waste material,and an ash pit for receiving burnt material, the combination therewithof means for automatically removing the burnt material from said ashpit, said means comprising a. conveyor means communicating with said ashpit and being operable to remove the burnt material therefrom,

b. drive means for imparting movement to said conveyor means, and

0. control means for actuating said drive means for a predeterminedperiod and in response to each operation of said charging means.

2. In an incinerator, as set forth in claim 1, wherein said chargingmeans comprises feeding means operable to automatically feed wastematerial into said combustion chamber in a periodic manner.

3. In an incinerator, as set forth in claim 2, wherein said feedingmeans comprises a charging door, and a single ram automatic feed means.

4. In an incinerator, as set forth in claim 2, wherein said feedingmeans comprises a double ram automatic feed means.

5. In an incinerator, as set forth in claim 1, wherein said conveyormeans (a) comprises an endless drag chain having an upper reachextending through the bottom of said ash pit, an entry opening in oneside of said ash pit and an exit opening in the opposite side of saidash pit for entry and exit of said drag chain, a doctor gate supportedfor vertical movement in said exit opening of said ash pit and abovesaid drag chain, and means for adjusting the vertical position of saiddoctor gate above the upper level of said drag chain to thereby aid indetermining the amount of waste material removed from said ash pit bysaid drag chain.

6. In an incinerator, as set forth in claim 5, including a burntmaterial elevator conveyor having one end portion positioned beneathsaid upper reach of said drag chain for receiving burnt materialtherefrom, said elevator extending upwardly therefrom for elevating theburnt material and discharging the same at a level above said dragchain.

7. In an incinerator, as set forth in claim 6, wherein said drive meanscomprises a first electric motor drivingly connected to said drag chain,and a second electric motor drivingly connected to said burnt materialelevator conveyor.

8. In an incinerator, as set forth in claim 7, wherein said firstelectric motor is operable in response to operation of said controlmeans, and wherein said second electric motor is continuously operatedindependently of said control means.

9. In an incinerator including a combustion chamber for burning wastematerial, and an ash pit for receiving burnt material, the combinationtherewith of means for automatically removing the burnt material fromsaid ash pit, said means comprising:

a. conveyor means communicating with said ash pit and being operable toremove the burnt material therefrom,

b. drive means for imparting movement to said conveyor means, and

c. control means for actuating said drive means for a predetermined timeperiod and in response to each operation of said charging means andincluding temperature sensing means positioned in said ash pit forpreventing the operation of said drive means and for stopping the normaloperating period of said drive means when the accumulation of burntmaterials in said ash pit is reduced below a predetermined amount whichcauses the temperature in said ash pit to exceed a predetermined level.

10. In an incinerator, as set forth in claim 9, wherein said conveyormeans comprises an endless drag chain having an upper reach extendingthrough the bottom of said ash pit, and a burnt material elevatorconveyor having one end positioned beneath said upper reach of said dragchain for receiving burnt materials therefrom and extending upwardlytherefrom for elevating the burnt materials and discharging the same ata level above said drag chain.

11. In an incinerator, as set forth in claim 10, wherein said drivemeans comprises a first electric motor drivingly connected to said dragchain and operable in response to operation of said control means, and asecond electric motor drivingly connected to said burnt materialelevator conveyor and being continuously operated independent of saidcontrol means.

12. In an incinerator, as set forth in claim 9, wherein said controlmeans further includes an adjustable control switch operativelyconnected to said temperature sensing means for selectively varying thepredetermined temperature level at which the normal operating period ofsaid drive means is stopped.

1. In an incinerator including a combustion chamber for burning wastematerial, means for charging the combustion chamber with waste material,and an ash pit for receiving burnt material, the combination therewithof means for automatically removing the burnt material from said ashpit, said means comprising a. conveyor means communicating with said ashpit and being operable to remove the burnt material therefrom, b. drivemeans for imparting movement to said conveyor means, and c. controlmeans for actuating said drive means for a predetermined period and inresponse to each operation of said charging means.
 2. In an incinerator,as set forth in claim 1, wherein said charging means comprises feedingmeans operable to automatically feed waste material into said combustionchamber in a periodic manner.
 3. In an incinerator, as set forth inclaim 2, wherein said feeding means comprises a charging door, and asingle ram automatic feed means.
 4. In an incinerator, as set forth inclaim 2, wherein said feeding means comprises a double ram automaticfeed means.
 5. In an incinerator, as set forth in claim 1, wherein saidconveyor means (a) comprises an endless drag chain having an upper reachextending through the bottom of said ash pit, an entry opening in oneside of said ash pit and an exit opening in the opposite side of saidash pit for entry and exit of said drag chain, a doctor gate supportedfor vertical movement in said exit opening of said ash pit and abovesaid drag chain, and means for adjusting the vertical position of saiddoctor gate above the upper level of said drag chain to thereby aid indetermining the amount of waste material removed from said ash pit bysaid drag chain.
 6. In an incinerator, as set forth in claim 5,including a burnt material elevator conveyor having one end portionpositioned beneath said upper reach of said drag chain for receivingburnt material therefrom, said elevator extending upwardly therefrom forelevating the burnt material and discharging the same at a leVel abovesaid drag chain.
 7. In an incinerator, as set forth in claim 6, whereinsaid drive means comprises a first electric motor drivingly connected tosaid drag chain, and a second electric motor drivingly connected to saidburnt material elevator conveyor.
 8. In an incinerator, as set forth inclaim 7, wherein said first electric motor is operable in response tooperation of said control means, and wherein said second electric motoris continuously operated independently of said control means.
 9. In anincinerator including a combustion chamber for burning waste material,and an ash pit for receiving burnt material, the combination therewithof means for automatically removing the burnt material from said ashpit, said means comprising: a. conveyor means communicating with saidash pit and being operable to remove the burnt material therefrom, b.drive means for imparting movement to said conveyor means, and c.control means for actuating said drive means for a predetermined timeperiod and in response to each operation of said charging means andincluding temperature sensing means positioned in said ash pit forpreventing the operation of said drive means and for stopping the normaloperating period of said drive means when the accumulation of burntmaterials in said ash pit is reduced below a predetermined amount whichcauses the temperature in said ash pit to exceed a predetermined level.10. In an incinerator, as set forth in claim 9, wherein said conveyormeans comprises an endless drag chain having an upper reach extendingthrough the bottom of said ash pit, and a burnt material elevatorconveyor having one end positioned beneath said upper reach of said dragchain for receiving burnt materials therefrom and extending upwardlytherefrom for elevating the burnt materials and discharging the same ata level above said drag chain.
 11. In an incinerator, as set forth inclaim 10, wherein said drive means comprises a first electric motordrivingly connected to said drag chain and operable in response tooperation of said control means, and a second electric motor drivinglyconnected to said burnt material elevator conveyor and beingcontinuously operated independent of said control means.
 12. In anincinerator, as set forth in claim 9, wherein said control means furtherincludes an adjustable control switch operatively connected to saidtemperature sensing means for selectively varying the predeterminedtemperature level at which the normal operating period of said drivemeans is stopped.